There’s a new Most Wanted suspect on the nutrition hit list, and it may be bringing down one of the good guys with it.

The No. 1 villain in the American diet is no longer fat or cholesterol or even calories. Sure, they all had their run, but science has determined they’re not as guilty of making us fat and unhealthy as once thought.

Fat, we now know, doesn’t necessarily make you fat. (I know, right?)

In fact, by increasing satiety, fat can actually help you eat less. Cholesterol in food doesn’t necessarily result in cholesterol building up on artery walls. And simply cutting calories doesn’t necessarily result in weight loss — you’ve got to cut the right kind of calories.

Which is why today’s No. 1-with-a-bullet dietary bad boy is sugar.

Unfortunately, as more people try to avoid sugar, some are passing on fruit, too. And that’s a mistake.

If you happened to catch the documentary “Fed Up” during its all-too-brief theatrical run in Kansas City, you learned that addiction to sugar can be just as strong as an addiction to cocaine. And that eating sugar lights up the same pleasure centers of the brain as shooting up heroin.

Trouble is, avoiding sugar can be hard, since so many foods sneak in added sugar.

These include no-duh! things like candy bars and soda, as well as more surprising culprits like spaghetti sauce (7 grams of added sugar per serving), instant oatmeal (12 grams) and sports drinks (14 grams).

Federal guidelines call for kids to eat no more than 6 to 9 teaspoons of sugar a day. Yet a bowl of Froot Loops and an 8-ounce glass of orange juice — a typical meal fed to kids in the national school breakfast program — contains 11 teaspoons of sugar. So a kid has blown through his limit and it’s not even 10 a.m. yet.

So yeah, sugar’s a problem. Especially sugar-laden processed foods. But avoiding fruit because it contains sugar would be like throwing the good-for-you baby out with the sugary bath water.

While fruit does indeed contain sugar — that’s why it tastes so good — there’s no proof that eating it has the same detrimental health effects as eating processed foods with added sugar. In fact, a recent study found that increased fruit consumption is neatly tied to reductions in both body weight and risk of obesity-related diseases.

“Sugar in foods is absorbed by the body within minutes,” explained Georgiana Gross, faculty dietitian at the University of Texas Health Science Center’s School of Dentistry. “That quickly raises blood sugar levels and can, in time, lead to diabetes. Plus, the body uses stored vitamins and minerals to digest sugar, so it truly is empty calories.”

What makes fruit different is the fiber it contains.

“The fiber makes eating fruit OK,” said Dr. Robert Lustig, a pediatric endocrinologist at the University of California, San Francisco. His YouTube video “Sugar: The Bitter Truth” has been viewed almost 5 million times.

According to Lustig, the fiber in fruit slows the rate that sugar is absorbed so blood sugar rises more gradually. This also gives the good bacteria in your gut more time to consume the sugars themselves, keeping them happy and healthy. And as researchers have recently discovered, a healthy microbiome helps keep you happy and healthy, too.

It almost doesn’t matter which fruit you eat. The more sugar they contain, the more fiber they have, too. The only exception: grapes. Lustig calls them “big bags of sugar.”

The good news is that word is getting out about how bad sugar is for you. The Food and Drug Administration’s proposed changes to the Nutrition Facts label on packaged foods, for example, would include a category for “added sugars,” so consumers can see that a supposed “healthy” food such as flavored yogurt may contain as many as 19 grams of sugar.